sql join on code example

Example 1: only join in sql

They are functionally equivalent, but INNER JOIN can be 
a bit clearer to read, especially if the query has 
other join types (i.e. LEFT or RIGHT or CROSS) 
included in it.

Example 2: how to join tables in sql

JOINING 2 Tables in sql

SELECT X.Column_Name , Y.Column_Name2
FROM TABLES1_NAME X 
INNER JOIN TABLES2_NAME Y ON X.Primary_key = Y.Foreign_key;


--FOR EXAMPLE
--GET THE FIRST_NAME AND JOB_TITLE
--USE EMPLOYEES AND JOBS TABLE
--THE RELATIONSHIP IS JOB_ID

SELECT E.FIRST_NAME , J.JOB_TITLE
FROM EMPLOYEES E
INNER JOIN JOBS J ON J.JOB_ID = E.JOB_ID;

Example 3: sql server joins

SELECT Orders.OrderID, Customers.CustomerName, Orders.OrderDate
FROM Orders
INNER JOIN Customers ON Orders.CustomerID=Customers.CustomerID;

Example 4: join three tables sql

Suppose we are having three table named as 
Student_details
Attendance_details
Batch_details
And we have to apply join these three tables for fetching records

Example query:
select column_names
from Student_detail as s join Attendance_details as a on
s.s_id = a.s_id join Batch_details as b on 
s.s_id = b.s_id;

Here in the above example we implemented simple join but you change it with own join requirements.

Example 5: MySQL Join

A relational database consists of multiple related tables linking together using common columns which are known as foreign key columns. Because of this, data in each table is incomplete from the business perspective.
MySQL supports the following types of joins:

Inner join
Left join
Right join
Cross join

The following shows the basic syntax of the inner join clause that joins two tables table_1 and table_2:

SELECT column_list
FROM table_1
INNER JOIN table_2 ON join_condition;


SELECT column_list
FROM table_1
INNER JOIN table_2 USING (column_name);

SELECT column_list 
FROM table_1 
LEFT JOIN table_2 USING (column_name);
Here is the syntax of the right join:

SELECT column_list 
FROM table_1 
RIGHT JOIN table_2 ON join_condition;

The following shows the basic syntax of the cross join clause:

SELECT select_list
FROM table_1
CROSS JOIN table_2;

Example 6: joins in sql

INNER JOIN:
is used when retrieving data from multiple
tables and will return only matching data.

LEFT OUTER JOIN:
is used when retrieving data from
multiple tables and will return
left table and any matching right table records.

RIGHT OUTER JOIN:
is used when retrieving data from
multiple tables and will return right
table and any matching left table records

FULL OUTER JOIN:
is used when retrieving data from
multiple tables and will return both
table records, matching and non-matching.



INNER JOIN :
SELECT select_list From TableA A
Inner Join TableB B
On A.Key = B.Key


LEFT OUTER JOIN :
SELECT select_list From TableA A
Left Join TableB B
On A.Key = B.Key

(where b.key is null)//For delete matching data



RIGTH OUTER JOIN :
SELECT select_list From TableA A
Right Join TableB B
On A.Key = B.Key


FULL JOIN :
SELECT select_list From TableA A
FULL OUTER Join TableB B
On A.Key = B.Key